DE60311114T2 - AVERAGE VALUE QUADRAT ESTIMATE OF CHANNEL QUALITY MEASUREMENT - Google Patents

Description

BACKGROUND

area

The The present invention relates generally to communications and in particular, analyzing the feedback channel information that can be used to schedule and the rate control of traffic over one To improve wireless communication system.

background

In A wireless communication system may include a receiver, such as a Mobile station, channel conditions monitor the shipments received, such as the carrier-to-interference ratio (C / I carrier-to-interference), and report such information to the sender, such as to the serving base station. The Base station then uses this knowledge to broadcasts to the remote station optionally to plan.

In Communication systems that use feedback mechanisms to perform the quality of the transmission medium, channel conditions are continuously on the Transfer reverse link. Errors that occur in such programs affect the efficient allocation of resources, the quality of subsequent ones Shipments as well as influencing the performance of the system. Typically, a complex algorithm and calculation at Transmitter (i.e., an item receiving the quality feedback information) the accuracy of the received quality feedback information determine. There is a need for accuracy and reliability the quality feedback information to verify. There is still a need, the complexity of a to reduce such verification.

"Utilizing Quantized Feedback Information in Orthogonal Space-Time Block Coding, "Jöngren et al., published on 27 November 2000, like the presence of vector quantized channel information obtained from a feedback link can be applied to improve the Performance of a space-time code.

The The present invention relates to a method, a wireless Device and a base station as defined in the appended claims.

SHORT DESCRIPTION THE DRAWINGS

1 Fig. 10 is a diagram illustrating a forward link and reverse link in a communication system;

2 is a diagram of a wireless communication network.

3A . 3B and 3C are timelines describing the interactions between the resynchronization subresynchronization subchannel and the difference feedback subchannel.

4 Figure 12 is a block diagram of a remote station in communication with a base station.

5 is an illustration of the codewords for link quality measurements.

6 FIG. 10 is a timing diagram of the transmission of full-connection quality codewords associated with the link quality measurements and difference indicators.

7 FIG. 10 is a flowchart of a method for evaluating link quality indicators.

8th FIG. 10 is a flowchart of a method for evaluating difference indicators.

DETAILED DESCRIPTION

The The field of wireless communications has many applications, including the Example wireless telephones, paging, wireless local loops, personal digital assistants (PDAs = personal digital assistants), Internet telephony and satellite communication systems. A particularly important application are cellular telephone systems for mobile subscribers. As used herein, the term "cellular" system encompasses both cellular as well as personal Communication Service (PCS) frequencies. Various over-the-air interfaces were for developed such cellular telephone systems, including for Example of frequency division multiple access (FDMA) multiple access), time division multiple access (TDMA) multiple access) and code division multiple access (CDMA = code division multiple access). In connection with it were different developed national and international standards, including for Example Advanced Mobile Phone Service (AMPS), Global System for Mobile (GSM) and Interim Standard 95 (IS-95). IS-95 and its derivatives, IS-95A, IS-95B, ANSI J-STD-008 (often referred to herein as IS-95) and proposed high data rate systems were used by the Telecommunication Industry Association (TIA) and other known standard entities released.

cellular telephone configured according to use the IS-95 standard, apply CDMA signal processing techniques to highly efficient and to provide robust cellular telephone service. Exemplary cellular telephone systems, essentially configured according to use the IS-95 standard, are described in U.S. Patent Nos. 5,103,459 and 4,901,307, assigned to the assignee of the present invention. An exemplary system that uses the CDMA techniques is the CDMA-2000 ITU-R Radio Transmission Technology (RTT) Candidate Submission (referred to as cdma2000), published by the TIA. The standard for cdma2000 is available in the pre-release versions of the IS-2000 accepted by the TIA and 3GPP2. Another CDMA standard is the W-CDMA standard, as stated in the 3rd Generation Partnership Project "3GPP", with the documents Nos. 3G TS 25.211, 3G TS 25.212, 3G TS 25.213 and 3G TS 25.214.

The Telecommunication standards cited above are examples of only some of the different communication systems that are implemented can be. Some of these different communication systems are configured so far stations are able to provide information regarding the quality of the transmission medium to a serving base station. These Channel information can subsequently used by the serving base station to measure the power levels, Transmission formats and timing of forward link transmissions optimize and further the power levels of the reverse link transmissions to control.

As used herein, the "forward link" refers to the shipments, which is directed from a base station to a remote station are and "reverse links" refers to the broadcasts going from a remote station to a base station are directed. The fast fade on the forward link and the reverse link are uncorrelated, i. that the observations of the one not necessarily information about deliver the other.

Channel states of received forward link transmissions, such as the carrier-to-interference ratio (C / I) can be watched by a remote station providing such information reported to a serving base station. The base station used subsequently this knowledge to select broadcasts to the remote station to plan selectively. For example, if the remote station has the presence of a deep fading would report refrain from scheduling a program until the base station stops Deterioration is over. Alternatively, the base station may decide to schedule a broadcast but at a high transmit power level, to compensate for the fading condition. Alternatively, the base station decide to change the data rate sent with the broadcasts, namely by sending the data in formats carrying more bits of information can. If, for example, the channel conditions are bad are, can Data is sent in a broadcast format with redundancies, so that damaged or erroneous symbols are more likely to recover. As a result, the data throughput is lower than if a broadcast format instead without redundancies would be used.

The base station may also use this channel information to balance the power levels of all remote stations within the operational area so that reverse link transmissions arrive at the same power level. In CDMA-based systems, channeling between the remote stations is produced through the use of pseudo-random codes that allow a system to superpose many signals on the same frequency. Consequently, a Rückwärtsverbin A power operation control is an essential operation of the CDMA based systems because excessive transmit power transmitted by a remote station could \ "override \" or \ "drown out \" broadcasts from their neighbors.

In Communication systems that use feedback mechanisms to perform the quality of the transmission medium, channel conditions are continuously on the Transfer reverse link. This produces a big one Load on the system that consumes system resources, otherwise could be assigned to other functions.

As in 1 Shown are transmission links in a wireless communication network 100 in terms of the direction of propagation between a base station (BS) 104 and a mobile station (MS = Mobile Station) 102 Are defined. Communications from the BS 104 to the MS 102 are sent over the forward link (FL = Forward Link). The forward link is from the BS 104 controlled, which determines the transmission power and data rate for data transmissions. Communications from the MS 102 to the BS 104 are sent via the reverse link (RL). The MS 102 measures the quality of the FL and sends an indication of the measured quality to the BS 104 on the RL. The MS 102 can measure the C / I or other signal-to-noise ratio (SNR) on the received signals. The MS 102 can quantize the measurements and send the quantized values. The BS 104 then uses the quality information to implement the control of the FL.

The network or system 100 a plurality of MSs (also referred to as remote stations, subscriber units or user equipments), a plurality of BSs (also referred to as Base Station Transceivers (BTSs) or Node B in a data communication system such as the High Data Rate System (HDR), as described by 3GPP2, a Base Station Controller (BSC) (also referred to as a Radio Network Controller or Packet Control Function), a Mobile Switching Center (MSC), a Packet Data Serving Node (PDSN) or Internetworking Functions (IWF = Internetworking Function), a public switched telephone network (PSTN) (typically a telephone company) and / or an Internet Protocol (IP) (typically the Internet). 2 represents a system that contains the various components. For the sake of simplicity, there are four mobile stations 12a - 12d , three base stations 14a - 14c , a BSC 16 , an MSC 18 and a PDSN 20 shown. It should be noted by those skilled in the art that there are more or fewer mobile stations 12 , Base stations 14 , BSCs 16 , MSCs 18 and PDSNs 20 could give.

In one embodiment, the wireless communication network is 10 a packet data service network. The mobile stations 12a - 12d may be any of a number of different types of wireless communication device, such as a portable telephone, a cellular telephone connected to a laptop computer running IP-based web browser applications, a cellular telephone with associated hands-free devices, a Personal Data Assistant (PDA) Assistant) running IP-based web browser applications, a wireless communication module built into a portable computer, or a fixed-site communication module that could be found in, for example, a wireless local loop or a meter reading system. In the most general embodiment, the mobile stations could be any type of communication unit.

The mobile stations 12a - 12d may be advantageously configured to perform one or more wireless packet data protocols, such as described in the EIA / TIA-IS-707 standard. In a particular embodiment, the mobile stations generate 12a - 12d IP packets for the IP network 24 and encapsulate the IP packets in frames using a point-to-point protocol (PPP).

In one embodiment, the IP network is 24 with the PDSN 20 coupled, the PDSN 20 is with the MSC 18 coupled, the MSC is with the BSC 16 and the PSTN 22 coupled and the BSC 16 is with the base stations 14a - 14c coupled via wireline configured for transmission of voice and / or data packets according to any one of several known protocols, for example E1, T1, Asynchronous Transfer Mode (ATM), IP, PPP, Frame Relay, HDSL , ADSL or xDSL. In an alternative embodiment, the BSC 16 directly with the PDSN 20 be coupled.

During the typical operation of the wireless communication network 10 receive and demodulate the base stations 14a - 14c Sets of reverse signals from different mobile stations 12a - 12d involved in telephone calls, web browsing or other data communications. Any backward signal coming from an existing base station 14a - 14c is received within the base station 14a - 14c processed. Every base station 14a - 14c can with a variety of mobile stations 12a - 12d by modulating and transmitting sets of forward signals to the mobile stations 12a - 12d communicate. As in 2 For example, the base station communicates 14a with first and second mobile stations 12a . 12b at the same time and base station 14c communicates with the third and fourth mobile stations 12c . 12d simultaneously. The resulting packets become the BSC 16 which provides call resource allocation and mobility management functionality, including orchestrating soft handoffs of a call for a particular mobile station 12a - 12d from a base station 14a - 14c to another base station 14a - 14c , A mobile station 12c For example, it communicates with two base stations 14b . 14c simultaneously. Eventually, if the mobile station 12c away from one of the base stations 14c moved, the call is transferred to the other base station 14b handed over (handed off).

If the program is a conventional telephone call, the BSC will 16 the received data to the MSC 18 The additional routing services for the interface with the PSTN 22 provides. If the broadcast is a packet-based broadcast, such as a data call for the IP network 24 , then the MSC 18 the data packets to the PDSN 20 direct the packets to the IP network 24 will send. Alternatively, the BSC heads 16 Packages directly to the PDSN 20 that packets to the IP network 24 sends.

In some communication systems are packets that carry traffic, divided into subpackets that occupy slots of a broadcast channel. Only for the simple representation becomes the nomenclature of a cdma2000 system used below. Such use is not meant to be Implementation of the embodiments to limit this to cdma2000 systems. Implementations in others Systems, such as WCDMA, can do without the scope of protection the embodiments, which are described herein to adversely affect.

The forward link from the base station to a remote station located within the Area of the base station operates, may have a plurality of channels. Some of the channels The forward link can do the following include, but are not limited to: a pilot channel, synchronization channel, Paging channel, fast paging channel, broadcast channel, Power control channel, allocation channel, control channel, one dedicated control channel, media access control channel (MAC = medium access control), fundamental channel, support channel, Support code channel and packet data channel. The reverse link from a remote station to a base station also has one Variety of channels on. Each channel carries different types of destination destination information. typically, traffic is carried on fundamental channels and traffic is carried on support channels or packet data channels. Support channels are usually dedicated channels, while packet data channels are usually signals wear that for different participants in a time and / or code multiplexed Way are determined. Alternatively, packet data channels become the same described as shared support channels. For the Purposes of the description of the embodiments Support channels and packet data channels are generally referred to herein as traffic channels.

voice traffic and traffic is typically encoded, modulated and spread, prior to transmission on either the forward or reverse links. Coding, Modulating and spreading can be implemented in a variety of formats become. In a CDMA system hangs the transmission format ultimately depends on the type of channel over which the voice traffic and traffic is sent, and the state of the channel described in terms of fading and interference can be.

predetermined Sending formats that are a combination of different transmission parameters can correspond used to simplify the choice of transmission formats. In an embodiment corresponds the broadcast format of a combination of any or all of following transmission parameters: the modulation scheme used by the system is used, the number of orthogonal or quasi-orthogonal codes, an identification of the orthogonal or quasi-orthogonal codes, the data payload size in bits that Duration of the message frame and / or details regarding the Coding schemes. Some examples of the modulation schemes that used in communication systems are the quadrature phase shift keying scheme (QPSK = Quadrature Phase Shift Keying), the 8-fold phase shift keying scheme (8-PSK = 8-ary phase shift keying) and 16-times quadrature amplitude modulation (16-QAM = 16-ary Quadrature Amplitude Modulation). Some of the different ones Coding schemes that can be optionally implemented are Convolutional coding schemes that implement at different rates or turbo coders having multiple coding steps, which are separated by interleaving steps.

orthogonal and quasi-orthogonal codes, such as the Walsh code sequences used to send the information to any remote station be channeled. In other words, Walsh code sequences become the forward link used to allow the system to superimpose multiple users, where each one or more orthogonal or quasi-orthogonal Codes are assigned, and indeed on the same frequency during the same time duration. A planning element in the base station is configured to the send format of each package, the rate of each Package and the slot times, about which each packet should be sent to a remote station, too Taxes. The terminology "package" is used to Describe system traffic. Packages can be divided into subpackages which have slots of a broadcasting channel. "Slot" is used to take a period of time Message frame. The use of such Terminology is common in cdma-2000 systems, but the usage of such terminology is not intended, the implementation the embodiments to limit this to cdma2000 systems. Implementation in others Systems, such as Wideband CDMA (W-CDMA) can do without the Scope of the embodiments, which are described herein to adversely affect.

To plan is an important component for achieving high data throughput in a packet-based system. In the cdma2000 system controls the scheduling element (also referred to as "scheduler" herein) packs payload in redundant and repeating subpackages that at a receiver soft combined (soft combined), so that when a received Subpackage is faulty, it with other faulty subpackages can be combined to reduce the data payload within an acceptable range Frame error rate (FER) to determine. If to For example, a remote station sending data at 76.8 kbps requests, but the base station knows that this sending rate is not possible is at the requested time, because of the state of the channel the scheduler in the base station packing the data payload into several Control subpackages. The remote station will be several faulty Subpackets, but will probably still be the data payload by soft-combining the healthy bits of the subpackets. As a result, the current transmission rate of the bits may be of the data throughput rate to be different. The planning element used in the base station a control algorithm or open-loop algorithm (open-loop algorithm) to adjust the data rate and the forward link transmissions to plan. The open-loop algorithm fits the programs according to the varying ones Channel conditions, typically found in a wireless environment. In general, the remote station measures the quality of the forward link channel and sends such information to the base station. The base station uses the received channel states around the most efficient transmission format, rate, To predict the power level and timing of the next parcel shipment. In the cdma2000 1xEV-DV system can the remote stations provide a channel quality indication feedback channel (CQICH = Channel Quality Indicator Feedback Channel) for channel quality measurements of the best utility sector to the base station. The channel quality may be in terms of carrier-to-interference ratio (C / I) and is based on the received forward link signal. The C / I value is set to a five-bit channel quality indication symbol (CQI = Channel Quality Indicator), where the fifth bit is reserved. As a result, the C / I value can be one out of sixteen Have quantization values.

There the remote station is not foreknowledge sends the remote station the C / I values continuously, so that the base station knows of the channel conditions whenever any Packages on the forward link to be sent to this remote station. The continuous Transmission of 4-bit C / I values consumed the battery life of the remote station by occupying the hardware and software resources in the remote station.

In addition to There are problems of battery life and reverse link load as well a problem of latency or delay. Because of the spread and because of processing delays, the base station plans to stop shipments using no more current information. If the typical propagation delay is 2.5 ms, that of a 2-slot delay in Systems with 1.25 ms slots, then the base station respond to a situation that no longer exists or can to respond to a new situation in a timely manner.

Out the above reasons need the communication network has a mechanism to provide information about To transmit base station, allowing the base station to reschedule shipments quickly, because of sudden changes in the channel environment. additionally The mechanism mentioned above should reduce battery consumption Reduce the distance to the remote station and reduce the load on the reverse link.

In an embodiment be complete C / I values on a re-synchronization subchannel sent while incremental 1-bit values via a difference feedback subchannel are sent. The incremental 1-bit values of 1 and 0 are mapped to + 0.5dB and -0.5dB but can also to other values ± K where K is a system-defined step size.

The Values sent on resynchronization and resynchronization and difference feedback subchannels are determined based on the forward link C / I measurements. The value sent on the resynchronization sub-channel is obtained by quantizing the last C / I measurement. A one-bit value is sent on the difference feedback subchannel and is passed through Compare the last C / I measurement with the contents of an internal one Register received. The internal register is updated based on on the last values sent on the resync and difference feedback subchannels and represents the best estimate the C / I value of the remote station that the base station will decode.

In a first mode Channel elements are placed within a remote station to the resynchronization subchannel and the difference feedback subchannel via the CQI channel (CQICH), where the resynchronization subchannel occupying one slot of an N-slot CQICH frame and the difference feedback sub-channel all slots of the N-slot CQICH frame occupied, leaving an incremental one-bit value in each slot is sent.

In one embodiment, the resynchronization subchannel and the difference feedback subchannel are not sent in parallel. Instead, the resynchronization subchannel is sent over a slot and the system refrains from sending the difference feedback subchannel in that particular slot. In another embodiment, in at least one slot of the N-slot CQICH frame, both a complete C / I value and an incremental one-bit value are sent to the base station. This simultaneous transmission is possible through the use of orthogonal or quasi-orthogonal spreading codes or, in an alternative embodiment, by time-interleaving the two subchannels in a predetermined manner. 3A FIG. 13 is a timeline illustrating the transmission timing of the resynchronization channel and the differential feedback sub-channel operating in parallel in the later embodiment.

The Channel elements can be configured to generate the two subchannels, namely with the resynchronization channel operating at a reduced Rate. The resynchronization channel operates with a reduced Rate, if complete C / I value over at least two slots of an N-slot CQICH frame are spread becomes. The complete For example, C / I may be at a reduced rate of 2, 4, 8 or 16 slots of a 16-slot CQICH frame are sent. The difference feedback subchannel occupies each of the slots of the N-slot CQICH frame. As a result, an incremental one-bit value is sent in each slot, parallel to the resynchronization subchannel. The distant station should the complete Send C / I value at the reduced rate when the reverse link at unfavorable channel conditions suffers. In one embodiment the base station determines the reverse link channel states and sends a control signal to the remote station, the control signal for a station informs if the resynchronization subchannel with reduced Rate should operate or not. Alternatively, the remote station be programmed to make this determination independent.

In one implementation, two subchannels operate in parallel at a reduced rate, with a full C / I spread across all slots of an N-slot CQICH frame and each slot also carrying an incremental one-bit value. In an alternative embodiment, the difference feedback subchannel occupies each slot of the N-slot frame except the first slot. In yet another alternative embodiment, the difference feedback subchannel and the resynchronization subchannel are not sent in parallel at all; the resynchronization subchannel first operates over M slots and the difference feedback subchannel operates over the next N to M slots of the N-slot frame. 3B and 3C are timelines that represent the transmission timing of the resynchronization subchannel and the difference feedback subchannel. The remote station's internal register may be updated in the first, second or Mth slot, depending on the mode of operation in use.

In another embodiment can the full C / I value will also be sent in unplanned slots whenever the remote station determines that the C / I estimate held at the base station is out of sync. The base station continuously monitors the CQICH to determine if an unplanned, complete C / I value symbol present or not.

In yet another embodiment will the full C / I value sent only if the remote station determines that the C / I estimate, which is held at the base station is out of sync. In this embodiment will the full C / I value to be regular scheduled intervals not sent. A planning element in one Base station can be configured to listen to the channel information, those on the resynchronization subchannel and the difference feedback subchannel have been received, interpret the channel information be used by each subchannel to make broadcast decisions, which take into account the state of the channel. The planning element may comprise a processing element associated with a memory element coupled and communicative with the receiving subsystem coupled with the transmitting subsystem of the base station.

4 Figure 12 is a block diagram of some of the functional components of a base station with a scheduling element. A distant station 300 sends on the reverse link to a base station 310 , For a receiving subsystem 312 the received broadcasts are despread, demodulated and decoded. A planner 314 receives a decoded C / I value and orchestrates the appropriate transmission formats, power levels and data rates of the transmissions from the transmission subsystem 316 on the forward link. The base station 310 also includes a storage device 318 for storing the connection quality indicator information.

At the far station 300 receives a receiving subsystem 302 the forward link transmission and determines the forward link channel characteristics. A transmitting subsystem 306 sends such forward link channel characteristics to the base station 310 ,

In the embodiments described herein, the planning element may 314 be programmed to interpret the channel information received on the resynchronization subchannel along with the channel information received on the difference feedback subchannel or to interpret the channel information received on the resynchronization subchannel separate from the channel information on the channel Difference feedback subchannel were received. The scheduler may also be configured to perform a procedure to alternate which subchannel will be used to update the channel information.

If the remote station transmits the channel information becomes a service base station the complete C / I value (or other connection quality indicator) over one Slot and incremental values receive all the slits of the frame. In one embodiment can the scheduler be programmed to reset internal registers, which store the current state of the channel, the registers with the full one C / I value over one Slot of the resynchronization sub-channel was reset becomes. The incremental values coming from the difference feedback subchannel are received, then upon reception become the full C / I value, which is stored in the register, added. In one aspect will be the value that passes at the same time the slot with the full C / I value was sent, deliberately discarded because of the full C / I value already for this incremental value counts.

A The service base station can provide the full C / I value over several Slots and incremental values across all slots of the frame receive. In one embodiment estimates the utility base station the channel conditions at the time required for a packet transmission planned by accumulating the incremental values, those on the difference feedback subchannel received from the second slot to the Mth slot, where M is the number of slots over which the full C / I value is spread. This accumulated value then becomes the full C / I value added on the resynchronization subchannel via the M slots was received. In another embodiment This "accumulate-and-add" process can be done simultaneously with an independent Action for "up-down" bits to be performed, the C / I value updated in the register than by the incremental values directed, stored. As a result, the register which is the saves current channel state information, updated every time, when an incremental value is received and the register becomes subsequently with the accumulated value added to the complete C / I value, updated.

5 represents an image of the coded values, ie the quantized values of the C / I on the measured values of the C / I. A first storage device 120 stores the quantized values or the code values. A second storage device 130 stores the measured ranges of values associated with each of the codes. According to one embodiment, the map is as in FIG 5 illustrated, implemented in software or hardware that performs a calculation to transform the measured values into code values.

6 is a timing diagram of the transmission of quality measurements, both complete measurement displays and difference values. As shown, the full measurement gauge is labeled as such. Full measurement displays are sent between time t1 and t2 and between time t3 and t4. For each slot between the complete measurement displays, a difference value is sent. The complete quality measurement indicators or C / I values of one embodiment are 4 bits encoded. The full quality measurement indicators are followed by 15 up / down commands, ie difference values. The entire slot cycle is 16 slots. Each slot cycle of the complete C / I is updated at least once.

One embodiment provides a method for evaluating connection quality feedback information that applies to the margin applied by the planner is applied. According to such Ausfüh approximately example will the full or total link quality indicator received at the BS. The BS then calculates the probability Receiving the received codeword according to a C / I measurement, the the MS was made. The BS determines the estimate with a minimum mean quadratic errors using a state average calculation. The minimum mean squared error identifies the "best" estimated codeword and thus the best appreciated Link quality measurement. By determining the estimate Minimum Mean Square Error (MSE = Mean Square Error) of the connection quality measurement will be an estimate of the root-mean-square error RMS (Root Mean Square) of the RMS value. The estimates then become a planner sent the error estimate into an operating margin or area (margin). Using the MSE allows this Identify unexpected C / I values. Used for this purpose the procedure previous complete C / I differences to highest unexpected new complete To identify C / I values. The minimal MSE approach can as well to the difference indicators (i.e., up / down).

To determine the quality feedback indicator for the complete measurement indicator, which in the present embodiment is a C / I measurement {C i } = a set of codewords associated with the permissible complete C / I values (1), and be R = the received complete C / I codeword. (2)

The method determines an estimate of the received C / I using a minimum mean square error (MSE) calculation. The MSE estimator builds a state average calculation. The estimator is described as follows:

It Note that in equation (3), C / I represents the C / I measurement, namely associated with the code word Ci. There are n C / I codewords. With In other words, the C / I measurements are quantized and counted to a total of n codewords displayed. The estimator Equation (3) can be considered as an expected value operator E (), which gives the expected value of the measured C / I in the light of the received Value of the codeword.

The estimator described by the equation (3) evaluates P (C _i ) from previous complete values of the C / I measurements. The estimator maintains a running average and a standard deviation of the differences between the complete C / I measurements and estimates a probability distribution of equal values, ie P (C _i ). For each complete link quality indicator received, a conditional probability for each possible codeword is calculated in light of the received value. The codeword with a minimum mean squared error thus calculated is considered to be the "best guess". A method of determining the minimum mean square error is given, as in equation (3), but other embodiments may employ other calculation methods.

In the presently described embodiment, the connection quality indicator is a complete connection quality indicator. Alternative embodiments (including those that however, may incorporate alternative connection quality indicators, such as differential displays. Alternative methods for determining the likelihood that a received connection quality indicator corresponds to the originally transmitted may be applied. Furthermore, it may be possible to compare such probabilities via a subset of available codewords in the light of historical and / or current and current operational states, link quality indicators and other parameters of the system. For example, during the operation, one embodiment may compare only those codewords in the subset if only a subset of available codewords were received over a predetermined period of time.

In the evaluation P (C _i ), methods for increasing outlier resistance can be used. Outlier resistance refers to the robustness of the system with respect to the data that is abnormally different from the realistic data. Outlier data can degrade the parameter estimate. An example that is considered resistant to outlier data is as follows:

The next step is to estimate the RMS error given as the square root of:

7 illustrates the foregoing described embodiment when a complete link quality indicator has been received at a base station (BS). The procedure 200 of the 7 includes two modes of operation: (1) a first mode wherein the complete link quality indicators are analyzed without consideration of any intervening difference indicator; and (2) a second mode taking into account the intervening difference indicators. While a BS is used for the present discussion, the present embodiments are applicable to any wireless communication device that receives a connection quality indicator and is based on transmission decisions thereof.

According to the procedure 200 the BS receives a complete link quality indicator in step 202 , The processing continues in step 206 to update the variance and mean of the currently received data. The variance and mean information is stored in the memory of the BS. The result of step 20 4 updates the latest mean and variance information. An embodiment also retains the historical information and provides such information to the planner. In step 206 the process evaluates the probability P (C _j ), evaluated for j = 1, 2, ..., n, where n is the total number of codewords associated with the link quality measurements, ie, a set of available codewords. The probability P (C _j ) is a probability that the codeword j has been received.

The base station then determines in the decision diamond 208 whether differential indicators are considered in the analysis of the received complete link quality indicator, for example first mode or second mode; as described above. In other words, the present estimates will only be based on the last complete link quality indicators received or will the estimator be the difference indicators that preceded receiving the complete link quality indicator in step 202 take into account. An alternative embodiment may evaluate P (C _j ) over a subset of the set of available code words. In step 210 the process determines the mean squared error for each of the codewords in the step 208 were evaluated, and determines the codeword with a minimum mean squared error. The step 208 applies the equation (3) given above. The process then estimates the mean square error in the step 212 , The base station then provides the link quality information to the scheduler in the step 214 , The provision of such information, and in particular the reliability and trust information regarding the estimated received signals, is used to schedule the data transmissions in a system that supports data transmission.

now to 7 If the estimates and calculations include the previously received difference indicators, processing continues in step 216 to add a weighting function for use in the Determination of a mean square error of the difference indicator. Since the difference indicator is a binary indicator, there are two possibilities: positive or negative. The difference indicator is identified as b. The received difference indicator is given as x, where x is assumed to include a received energy E associated with the difference indicator and the noise N is included. The energy of each possibility (ie positive and negative) is evaluated to determine the minimum mean square error of each estimate. For example, at a given time, the received signal x is evaluated for both the case of a positive difference indicator and a negative difference indicator.

wobei e_i der mittlere quadratische Fehler der Schätzung i ist. Dies ergibt den minimalen mittleren quadratischen Fehler als

The BS may combine the newly received complete link quality indicator with the last received complete link quality estimate updated by the intervening difference indicator. In view of the embodiment in which the complete indicator is sent over a slot and the system refrains from sending the difference indicator in that particular slot, even though this information is one slot old, the BS can calculate the quadratic error E [x ^ -x ] ² minimize using two (independent) estimates, as follows: x ^ = αx ^ 1 + (1 - α) x ^ 2 , (6) where a weighting factor is given as follows:

where e _{i is} the mean square error of the estimate i. This gives the minimum mean squared error as

It It should be noted that the above description also refers to an embodiment wherein the system sends the difference indicator when it also the complete one Indicator sends. In this case, the information is not obsolete or not up-to-date anymore.

It should be noted that x ^ _{1 may represent} a first link quality estimate using only the last complete link quality indicator received, while x ^ ₂ may represent a second link quality estimate calculated without the use of the last complete link quality indicator received but rather the last complete one Used connection quality indicator and any subsequent intervening difference indicators that have been received applies. The first and second estimates each have a corresponding mean squared error, and equations (6) and (7) each weight for themselves accordingly.

Back to 7 and the second operation mode, in which the analysis of the received complete link quality indicator takes into consideration the intervening difference indicator, in step 216 in which the weighting factor α of equation (7) is calculated as above. Alternative embodiments may employ alternative methods for weighting the various terms involved in the estimate of the received samples x ^. It should be noted that if one of the mean squared errors of one estimate is very much smaller than the other, the smaller squared error estimate is considered the better guess. If e _{1 is} the smaller mean square error, then the e ₁ term in the denominator will increase α and thus emphasize the e ₁ term in equation (6). If e _{2 is} the smaller mean square error, then the e ₂ terms in the denominator and the numerator α will reduce, thus emphasizing the e ₂ expression in equation (6). In this way, the terms of equation (6) are weighted to favor the least mean square error estimate, which is considered the "best" or "better" estimate. It should be noted that also if the mean square error of estimate 1 (ie e ₁ ) is approximately equal to the mean square error of estimate 2 (ie e ₂ ), then α ≡ ½ and each of the terms on the right side of the equation (6) are equally weighted.

Back to 7 , the estimate of the received signal is in step 218 generated the Ge weighting factor of equation (7) to the calculation of equation (6) as above. Processing then continues in step 220 to the mean square error of the step 218 to minimize the calculated error. step 220 uses equation (8) as above. Processing then continues in step 214 to send the connection quality information to the planner.

As described, processing of the second mode prepares as in the steps 216 to 220 of the 7 shown an estimate of the received sample x ^ using two estimates: the first estimate x ^ ₁ represents the link quality indicator estimate using only the last received complete link quality indicator; while the second estimate x ^ _{2 represents} the estimate of the last received link quality indicator with the difference indicators applied thereto. Each estimate has a corresponding mean square error. Equations (6) and (7) apply weights to each estimate according to the relationship of mean square errors. It should be noted that in an alternative embodiment, when a new complete C / I is received, the transceiver may decide to ignore the last up / down decisions and return to the last received complete link quality measurement.

The Procedure used to calculate the difference indicators, i. Up / down signals to appreciate is described in the following equations. Let x be the representation of the received sample, E the representation of the received signal energy of the sample, b represent represent the difference value that was sent and N the noise that during added to the shipment has been. Equation (9) identifies the received signal after included Signal energy associated with the transmitted link quality indicator (Difference indicator) and noise is associated.

To minimize the mean squared error, calculate b using:

Of the Tangens hyperbolic is used to provide some guidance when the Energy of the received difference indicator is low. If the Energy of the received difference indicator is high, the sent difference indicator estimated with relative certainty. However, if the received difference indicator has low energy, there is uncertainty.

die folgendermaßen geschrieben werden kann:

The sequence of the difference indicator is provided as a sequence between the complete link quality indicators. In step n of the sequence of the difference indicator, in which each difference indicator represents Δ dB, the dB value is given as follows:

which can be written as follows:

Equations (12) and (13) mathematically describe the operation of accumulating the difference indicators (ie, up / down instructions). Equation (12) provides such calculations with respect to dB, while equation (13) provides such a calculation with respect to linear variables. The product is a log normal random variable (rv), depending on the last complete C / I. For lognormal distribution, the associated random variable is given as

The mean and variance of (C / I) (n) _linear can also be derived using the variance, which is calculated as follows:

One alternative embodiment uses an estimate of the last complete Link quality indicator, incorporates the information from previous difference indicators. A such estimate replaces equations (10) and (11).

8th FIG. 10 illustrates a method for evaluating the received difference indicators using previous received values to determine the accuracy of each received difference indicator. The process 400 begins with the definitions of equations (7) and (8). The mean square error is in the step 404 minimized in equation (9). step 406 applies a calculation as in equation (11). In step 408 the process calculates a mean and a variance of (C / I) (n) _linearly . step 410 evaluates the received difference indicator using the previous received values along with the mean and variance of (C / I) (n) _linearly .

the It should be noted by those skilled in the art that information and signals are used from each of a variety of different technologies and techniques represents can be. Data, instructions, commands, information, signals, Bits, symbols and chips can for example, throughout the description as tensions, currents electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. It should also be noted to those skilled in the art that the various illustrative logical blocks, Modules, circuits and algorithm steps associated with the embodiments, which are disclosed herein as electronic Hardware, computer software or combinations of both implemented can be. To clarify this interchangeability of hardware and software, were various illustrative components, blocks, modules, circuits and Steps generally re their functionality described. Whether such functionality as hardware or software is implemented depends from the particular application and development limitations, which are imposed on the whole system. The expert can described functionality in varying ways for implement any particular application, but such implementation decisions should not be interpreted as if they are leaving cause the scope of the present invention.

The various illustrative logic blocks, modules and circuits, that in conjunction with the embodiments, which are disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP = digital signal processor), an application-specific integrated Circuit (ASIC = application specific integrated circuit), a field programmable gate array (FPGA = field programmable gate array) or another programmable logical device, discrete Gate or transistor logic, discrete hardware components or any combination thereof that has been developed to those described above Perform functions. A general purpose processor can be a microprocessor, but in the Alternative, the processor can be any conventional processor, controller, Be microcontroller or state machine. A processor can as well as a combination of calculation devices, for example a combination from a DSP and a microprocessor, a variety of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration can be implemented.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be performed directly in hardware, executed in a software module by a processor, or a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, in registers, on the hard disk, on a removable disk, on a CD-ROM, or on any other storage medium, the is known in the art. An exemplary storage medium is at the Prozes so that the processor can read information from it and write information on it. In the alternative, the storage medium may be integrated in the processor. The processor and the storage medium may reside on an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may be located as discrete components in a user terminal.

The previous description of the disclosed embodiments is provided to enable every professional to produce and use the present invention. Various Modifications of these embodiments will be readily apparent to those skilled in the art and the original principles, which are defined herein to other embodiments be applied. Thus, it is not intended that the present Invention on the embodiments, which are shown herein to limit, but it is to the widest possible Scope of protection consistent with the principles and new features, which have been disclosed herein.

Claims (47)

A method for a wireless communication system, comprising: receiving a link quality indicator, wherein the link quality indicator is one of a plurality of link quality indicator values; Determining a conditional probability for each of the plurality of link quality indicator values; Selecting one of the plurality of link quality indicator values based on the conditional probabilities; Estimating a minimum mean square error of the conditional probabilities, wherein selecting one of the plurality of link quality indicator values takes into account the minimum mean square error, and wherein the received link quality indicator is a full link quality indicator; the method being characterized in that the received link quality indicator is a carrier to interference ratio measurement; and the method is further characterized in that estimating the minimum mean square error of the conditional probabilities comprises: calculating

where n is the total number of connection quality values, Ci represents each connection quality indicator, R represents the received connection quality indicator, P (|) is a conditional probability operator, P (Ci) is a probability distribution of the probable values of Ci, and i and j indices are. The method of claim 1, further comprising: estimating the RMS error of the mean squared error as

where (C / I) is an estimate of the link quality indicator. The method of claim 2, further comprising having: Schedule the connection shipments using the estimate the minimum mean square estimate and RMS error. The method of claim 1, further comprising having: Schedule for connection using the estimate the minimum mean square estimate. The method of claim 1, wherein each of the plurality of link quality indicator values of a quantized connection quality measurement corresponds. The method of claim 1, further comprising having: Estimate a probability distribution of the probable connection quality indicator values; and Save the estimate the probability distribution in a memory storage device. The method of claim 6, wherein estimating the Probability distribution further comprises: To chat an average value and a standard deviation according to the received connection quality indicator. The method of claim 6, wherein estimating the probability distribution further comprises

The method of claim 1, further comprising having: Determining a first estimate of the received link quality indicator; Determine a second estimate of the received link quality indicator using the previously received connection quality indicator; and Determine a third estimate received connection quality indicator as a function of first and second estimates. The method of claim 9, comprising Determine a weighting factor as a function of the first and second estimates; and Apply the weighting factor to the third estimate determine. The method of claim 10, wherein determining the weighting factor comprises: calculating

where e _{1 is} a mean square error of the first estimate and e _{2 is} a mean square error of the second estimate. The method of claim 11, wherein determining the third estimate comprises: computing x ^ = αx ^ ₁ + (1-α) x ^ ₂ , where x ^ _{1 is} the first and x ^ _{2 is} the second estimate. The method of claim 12, further comprising: calculating a minimum mean square error of the third estimate as

The method of claim 13, further comprising having: Planning for connection shipments based on the third estimate and the minimum mean square error. The method according to any one of the preceding claims, further comprising: Schedule a connection based on the third estimate. The method of claim 10, wherein the link quality indicator is total link quality correspond to measurements. A wireless device comprising: means for receiving a link quality indicator, wherein the link quality indicator is one of a plurality of link quality indicator values; Means for determining a conditional probability for each of the plurality of link quality indicator values; Means for selecting one of the plurality of link quality indicator values based on the conditional probabilities; Means for estimating a minimum mean square error of the conditional probabilities, wherein selecting one of the plurality of link quality indicator values considers the minimum mean square error, and wherein the received link quality indicator is an overall link quality indicator; wherein the wireless device is characterized in that: the received link quality indicator is a carrier to interference ratio measurement, and the wireless device is further characterized in that: the means for estimating the minimum mean squared error of the conditional probabilities comprises: means for determining or calculating from

where n is the total number of connection quality values, Ci represents each connection quality indicator, R represents the received connection quality indicator, P (|) is a conditional probability operator, P (Ci) is a probability distribution of probable values Ci, and i and j indices are. The apparatus of claim 17, further comprising: means for estimating the RMS error of the mean square error as

where (C / I) is an estimate of the link quality indicator. The method of claim 18, further comprising having: Means for scheduling a connection transmission under Use of the estimate the minimum mean square estimate. The device of claim 18, wherein each of the plurality of connection quality indicator values corresponds to a quantized connection quality measurement. The apparatus of claim 18, further comprising having: Means to appreciate a probability distribution of probable connection quality indicator values; and Means for storing the estimate of the probability distribution in a storage storage device. Apparatus according to claim 21, wherein said means for Estimate the probability distribution further has the following: medium for maintaining an average and a standard deviation, respectively the received connection quality indicator. The apparatus of claim 21, wherein the means for estimating the probability distribution further comprises:

The apparatus of claim 21, further comprising having: Means for determining a first estimate of received link quality indicator; medium for determining a second estimate of the received link quality indicator using a previous received link quality indicator; and Means for determining a third estimate of the received link quality indicator as a function of the first and second estimates. The device of claim 24, comprising: medium for determining a weighting factor as a function of the first one and second estimates; and Means for applying the weighting factor to the third one estimate to determine. The apparatus of claim 25, wherein the means for determining the weighting factor comprises: means for calculating

where e _{1 is} a mean square error of the first estimate and e _{2 is} a mean square error of the second estimate. The apparatus of claim 26 wherein the means for determining the third estimate comprises: means for calculating x ^ = αx ^ ₁ + (1-α) x ^ ₂ , where x ^ _{1 is} the first estimate and x ^ _{2 is} the second estimate is. The apparatus of claim 27, further comprising: means for calculating a minimum mean square error of the third estimate as:

The device of claim 28, further comprising having: Means to plan for connection shipments on the third estimate and the minimum mean square error. The device of claim 28, further comprising having: Means to plan for connection shipments on the third estimate. The method of any one of claims 1 to 16, further Has: Receiving a variety of different Link quality indicators, the one originally estimate that the original sent different indicator is one of two binary values, by: Determine a minimum mean square error for each the two binary values and Estimate of the original Sent as the binary Value according to the minimum mean square error. The method of claim 31, wherein determining a mean square error comprises: computing for each binary value

An apparatus according to any one of claims 17 to 30, further comprising: Means for receiving a plurality of different link quality indicators; and means for estimating an originally transmitted different indicator for each of the plurality of different link quality indicators, wherein the originally transmitted different indicator is one of two binary values by: determining a minimum mean squared error for each of the two binary values, and estimating the original transmitted as the binary value corresponding to the minimum mean square error. The method of claim 33, wherein determining a mean square error comprises: for each primary, calculate from

A base station comprising: a processor for processing computer readable instructions; and a memory device for storing computer readable instructions for: receiving a link quality indicator, wherein the link quality indicator is one of a plurality of link quality indicator values; Determining a conditional probability for each of a plurality of link quality indicator values; Selecting one of the plurality of link quality indicator values based on the conditional probabilities; Estimating a minimum mean quadratic error of the conditional probabilities, wherein selecting one of the plurality of link quality indicator values considers the minimum mean square error, and wherein the received link quality indicator is a full link quality indicator, wherein the base station is characterized in that the received Link indicator is a measurement of a carrier to interference ratio, and the base station is further characterized in that the computer readable instructions are further used to: calculate

where n is the total number of link quality values, Ci represents each link quality indicator, R represents the received link quality indicator, P (|) is a conditional probability operator, and i and j are subscripts. The base station of claim 35, wherein the computer readable instructions are further for: estimating the root mean square error RMS error

where (C / I) is an estimate of the link quality indicator. The base station of claim 36, wherein the computer-readable Instructions continue to serve for: the Schedule a connection using the estimate of the minimum mean square estimate and RMS error. The base station of claim 36, wherein the computer-readable Instructions continue to serve for: the Schedule a connection using the estimate of the minimum mean square estimate. The base station of claim 35, wherein the computer-readable Instructions continue to serve for: the Estimate a probability distribution of the probable connection quality indicator values; and the Save the estimate the probability distribution in a memory storage device. The base station of claim 39, wherein the computer-readable Instructions continue to serve for: the Maintain a mean and standard deviation accordingly the received link quality indicator. The base station of claim 35, wherein the computer-readable Instructions continue to serve for: the Determining a first estimate the received connection quality indicator; the determining a second estimate received connection quality indicator using a previous received link quality indicator; and the determining a third estimate of the received link quality indicator as a function of first and second estimates. The base station of claim 41, wherein the computer-readable Instructions continue for The following serve: Determining a weighting factor as one Function of the first and second estimates; and Apply of the weighting factor to determine the third estimate. The base station of claim 42, wherein the computer readable instructions are further for: calculating

where e _{1 is} a mean square error of the first estimate and e _{2 is} a mean square error of the second estimate. The base station of claim 43, wherein the computer-readable instructions further serve to compute x ^ = αx ^ ₁ + (1-α) x ^ ₂ , where x ^ _{1 is} the first estimate and x ^ _{2 is} the second estimate. The base station of claim 44, wherein the computer-readable instructions are further for: calculating a minimum mean square error of the third estimate as:

The base station of claim 45, wherein the computer-readable Instructions continue for Serve the following: Plan for connection shipments on the third estimate and the minimum mean square error. The base station of claim 45, wherein the computer-readable Instructions continue for Serve the following: Plan for connection shipments on the third estimate.